I find most landlords if you start pushing for addendums do one of two things: they immediately shut down, which is usually an indicator they're going to be difficult anyway. Or they don't care enough and they'll wave it away just to get you in the door, especially when the clause you are disputing is insignificant and looking for someone else could cost them 5x or more what that little clause was worth anyway because of a missed month.

This is obviously contingent on a lot of things. Do you need to move now? Is it incredibly difficult to find anything and this checks off every other box? Etc. But just something to consider if you have room to abandon ship on a rental you find.